Yes you are so right there are fake big name cables on E-Bay every day.
chinese counterfeitng
I own dartzeel amp and preamp. I was checking out pricing and noticed dartzeel amp selling for $650 on ebay. I checked into this and they make it look externally the same but obviously not internally. The sellers were mainly from China. If they can make the amp look real I bet is would be an easy process to fake a cable or anything else for that matter